The way I see it, it takes a very selfish person to be a billionaire in the first place— one that not only doesn't care about people today, but also doesn't care about future generations of humans, let alone other living beings.

Any billionaire pointing at space exploration as humanity's salvation is, IMO, either really just craving the attention and glory of conquest (much like Caesar, Napoleon, Alexander, etc) or seeking the conditions of the age of exploration (XV to XIX centuries), when companies were as powerful as governments and expansionism was unfettered.